The standard metallographic preparation procedure for hard materials or soft materials does not produce satisfactory results for a composite material comprised of hard or refractory materials and soft materials. The standard polishing procedure when performed on a composite material using 0.3 micron alumina and 0.05 micron alumina on a microcloth on a polishing wheel rounded the refractory constituents and left them in relief, and the soft constituents were not scratch free. Thus, for microscopic examination and evaluation, a flat, scratch-free representative sample is required.
An object of this invention is to provide a metallographic preparation procedure for obtaining a flat and scratch free surface of a representative sample of a pressed and sintered powder metallurgy material.
A further object of this invention is to provide a metallographic preparation procedure for obtaining a flat and scratch free surface of a representative sample of a pressed and sintered powder metallurgy material comprised of a composite of the refractory metals tungsten and columbium and the soft metals lead and copper.